Pendulum-scales



(N0 Model.)

J. B. MARTIN. PENDULUM SCALES.

No. 436,835. Patented Sept. 23, 1890.

UNITED STATES PATENT OFFICE.

JOHN B. MARTIN, OF CINCINNATI, OHIO.

PENDULUM-SCALES.

SPECIFICATION forming part of Letters Patent No. 436,835, dated September 23, 1890.

Application filed April 1, 1839. Serial No. 305,557. (No model.)

To in whom it may concern.-

Be it known that I, JOHN B. MARTIN, a citizen of the United States, residing at Cincinnati, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Pendulum-Scales; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

The several features of my invention and the various advantages arising from their use, con 3' ointly or otherwise, will be apparent from the following description and claims.

In the accompanying drawings, forming part of this specification, Figure'l is a side elevation of a scale embodying my invention. Fig. 2 is an elevation of that end of the scale which is at the left hand in Fig. 1. Fig. 3 represents a novel and useful means of preventing the knife-edge of the pivot from slipping laterally on that surface of the loop against which it bears, the side of the loop and its accompanying plate being cut away to allow the improvement to be better seen and understood.

A indicates the bed-plate or foundation of the machine, of any suitable description. Upon this bed-plate and suitably secured thereto is a yoke-shaped standard B. This standard B has two upright pieces B B each of which, near its lower end, curves inward and joins together, uniting at or near the bot tom of the standard at the point The portion 13 preferably extends down a short distance, as shown, and its free end is joined to the base by a screw extending through from the under side of the plate A and screwed into the said extension B. Each of the standards B 13 is respectively provided in its upper end with a hole or loop B capable of re ceiving a knife-edge, as hereinafter mentioned.

O is the dial-plate or quadrant, whose lower end is connected to the pendulum-weight D and whose upper end is connected to the arm E. This arm E is in turn rigidly connected to the upper arm F of the lever F F, the arm F of the lever being connected directly to the pendulum-weight D. At the junction of the arms F F of the lever is the axis G, the lever being rigidly connected to said axis near .be graduated on both sides.

the longitudinal center of the latter. This axis G is provided at both ends with a knifeedge G, pointing downward,which knife-edge rests in the holes or loops B of the standard or upright piece B and forms the fulcrum of the lever F F. There is also another axis or cross-piece H, parallel to axis G, rigidly connecting in its longitudinal center the arm E with the upper end of lever F. Each end of the cross-piece H is provided with a knife-edge bearing II, )ointing upward and supporting the platform I. The platform I of the scale may be of any desired shape, suitable for the reception of articles or things to be weighed. The platform I rests upon two upright supporting-stays J J These vertical supportting-stays J J are preferably connected together by a brace or strengthening-piece .I at

their upper ends, which not only unites them,

but is connected directly to the platform I. Each of these supporting-pieces is provided with a hole or loop J Into these respective holes or loops J the knife-edges H of the axis H respectively enter. These knife-edges II respectively work within their respective loops J and the respective supporting-pieces rest upon their respective knife-edges H and are supported thereby. The vertical supporting-stays .I J 2 extend downwardly, preferably,about three-fourthsthe length of standard B, and are respectively connected to the standards B 13 by links K for the purpose of holding the platform I in a vertical position, one end of each link being pivoted to the lower end of its adjacent vertical stays J J and one end to its adjacent vertical standards B or B as the case may be.

The scale is provided with a suitable indicating pointer or pointers L, of which there are preferably two, one of these pointers L being on one side of-thc dial-plate or quadrant (3 and the other pointer being on the other side of the dial-plate or quadrant O. In such event the dial-plate or quadrant C will In this way the weight of an article placed upon the platform can be read standing at either side of the scale.

The provision of the two upright support ing-pieces B B of the standard provides a broad bearing-surface for steadying the lever F F and the parts E 0 connected therewith.

' flexible support for superincumbent working portions of the scale and the article placed upon the scale to be weighed. In the next.

place, the two supporting-stays J J are at a distance from each other and rest on the ends namely, the knife-edges I-Iof the axis H, which latter in turn is steadied by the axis G, well supporting and steadying the platform 'I. It will thus be seen that the scale is thoroughly braced against lateral deflection, and is thereby enabled to operate-namely, to weigh with great accuracy.

Attention is called to the fact that the knifeedges G point downward, while those H point upward, and also to the fact that the knife-edges H and G are attached rigidly to the lever F through the medium of their respective axesH and G. The great advantage which this afiords over previous scales is the following, viz: The knife-edges will always be at the same distance apart no matter in what position the quadrant 0 maybe in relation to the indicator or pointer L. For this reason the length of the arm F of the lever will always be the same in relation to the platform I, and the arm F of the lever will therefore weigh more accurately than it would if 'the knife-edges H were reversed in position and rigidly attached to the supportingstays J J and received in a hole or loop provided at the junction of the parts E and F. In the latter case, obviously, the point of the knife-edge 11 would 'recede from or approach toward the knife-edge G, according as the 'q'uadrant was depressed or elevated, thus lengthening or shortening the leverage and causing the dial-plate to register weight erroneously.

In my improved construction the knifepivots H and G, for both the pendulumweight and scale-pan, being fixed'in two stationary armsE and F F, as aforementioned, preserve the uniformity in the interrelative position of the said knife-edges, thereby securing the most accurate weight. In place of using knife-edge pivots the weight may swing upon pin-points; but the knife-edges are preferable on account of durability and havingaless tendency to Wear a depression in the bearing-surface of the loop. Ordinarily the knife-edge will not slip upon that surface of the loop which it engages and against which it bears. It will, however, often happen that when an article to be weighed is suddenly placed upon'the platform and the quadrant is suddenly canted to one side the knife-edges will slide a little upon the bearing-surface of their respective loops. Any such sliding or slipping of the knife-edge on the bearing will to some extent vary the accuracy of the scale. I have invented a provision for preventing this slipping of the position of the knife-edge in relation to the bearing. This provision is as follows: From the lower portion of the end of the knife-edge G extends outwardly a teat or lug G This lug extends into and fits closely but turns readily within an opening B in a plate or lug B, either cast to or otherwise suitably secured to the vertical standard B carrying the loop B The lower edge of the teat or lug G is preferably a continuation of the knifeedge of the bearing. It willbe seen thatby these means the knife-edgebearing cannotslip laterally, but on the contrary will always remain in its proper position for accurate weigh- 111". against the rear Wall of which the end of thelug G will strike before the shoulder G of the axis impinges against the side of the supportingstandard. As the friction of the small surface of the lug G against the end wall of. re-

cess B is much less than'the friction of the much larger surface of the shoulder G and the friction of the lug G is at a point in reference to the longitudinal axis of the part G,

The opening B is preferably a recess,

where the resistant leverage from frictional contact is necessarily much less, much friction will thereby be avoided. The lug G is preferably tapered to a point, and the opening B is preferably a tapered recess, sit-b stantially as shown in Fig. 3. This construction obtains all of the other advantageous results of my improved construction of these parts, and also diminishes theirfriction to a minimum. This device for preventing the knife-edge from slipping is to be applied to the other knife-edge bearings of the scale, and is not confined to the knife-edge bearings G, it being shown in Fig. 3 in connection with said bearing G for the purposes of illustration. Where the knife-edge points upward, the lug and the opening B which receives it, will be at the upper or top por tion of the bearing-loop.

While the various features of my invention are preferably employed together, one or more of said features may be used without the remainder, and in so far as applicable one or more of said features maybe used in connection with scales other than the one herein specifically described.

What I claim as new, and desire to secure by Letters Patent, is-- I 1. In a gravity-scale, the combinationof the standards B B levers F and F, quadrant 0,

having arm E, and rigidly connected to said v levers F and F, axis G, rigidly connected to said levers, the quadrant being pivoted on the standards at B and platform I, pivoted at H to the quadrant, the pivot H being located at the same side of the standards as is the quadrant, substantially as and for the purposes specified.

2. In a gravity-scale, the platform provided with the downwardly-extending standards J J located at a distance apart and engaging the ends of the axis G of the levers F F, combined with the quadrant and pendulum, the standards J J affording a broad basal support for the platform of the scale, substantially as and for the purposes specified.

3. In a gravity-scale, the levers F F and the axis G, the latter being rigidly connected to said levers F F at the point of their junction,and the platform provided with the downwardly-extended supporting-stays J J located at a distance apart and engaging the ends of the axis G G of the levers F F, and each provided at its lower ends with a link K, connected thereto and to the standards B B combined with the quadrant and pendulum, and the standards B B forming a broad basal support for the entire scale, substantially as and for the purposes specified.

4. The combination of a knife-edge and a pivotal bearing, viz: the knife-edge bearing having its free or outer end provided with a pivot, and the bearing opposing said knifeedge being provided with an opening or recess B which latter receives said pivot, substantially as and for the purposes specified.

5. The knife-edge bearing having the lug Gr extending from its end and at or near the line of its edge, and a supporting-piece having the loop receiving the main portion of the bearing, and having a recess B of smaller size than the loop and adapted to receive only the lug G the lug G' being tapered, and the recess 13 being correspondingly tapered,substantiall y as and for the purposes specified.

JOHN B. MARTIN. Attest:

F. W. BRoWNE, G. A. W. PARER. 

